Manager John Farrell said he noticed a change in Tazawa’s mental approach recently.

“There hasn’t been an adjustment delivery-wise or anything mechanically or fundamentally,” Farrell said. “It’s just been more with an aggressive attack mode rather than trying to be a little bit too fine.”

Said Saltalamacchia: “He’s had a lot of games where he’s thrown the ball well and he’s had some games where he makes one mistake and they hit it. Tonight he just hit his spots well. And really, that was key.”

Tazawa has been one of Boston’s most consistent relievers this season. His ERA peaked at 3.31 — and that was back on May 11.

But the 5-foot-11-inch, 200-pounder was showing some cracks entering the All-Star break. In his eight appearances entering the season’s midway point, Tazawa had a 5.87 ERA. In those 7⅔ innings, batters were hitting .333 with 10 hits and two home runs.

“There was a point three or four weeks ago where some fastballs leaked back to the middle of the plate,” Farrell said. “I think he was overcompensating by trying to cut the ball a little bit to keep it away from righthanders.”

On Tuesday, Tazawa delivered with confidence — something the Red Sox will count on down the stretch.

Tazawa’s role as a late inning reliever — and setup man for Uehara — gained extra importance when the team recently lost Andrew Miller and Andrew Bailey for the season.

“It’s not that my confidence level has changed,” Tazawa said. “I’m just gratified that the manager has used me in that kind of position.”

When Tazawa exits the bullpen, a Japanese pop song blasts on the speakers. The song is called “Mogura No Uta,” most closely translated to “Song of the Mole.”